Rajen Govender, Managing Director of Weir Minerals South Africa, talks about recent innovations at the company’s South African facilities and its efforts to support long-term sustainable growth in sub-Saharan Africa.
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Weir Minerals has installed solar systems on the roof of the Isando facility.
In support of the company’s extensive product range for the global mining, minerals processing, power and general industrial sectors of Africa, Weir Minerals Africa operates three manufacturing facilities in South Africa: “Here in Isando, we have a foundry for smaller castings of below 1.0 tonne, a machine shop and a rubber shop all operating on a three-shift basis. We also have our Heavy Bay Foundry (HBF) in Port Elizabeth that can handle larger castings of up to 17 t gross, and a pump assembly, screen assembly and rubber plant in Alrode” says Rajen Govender, Managing Director of Weir Minerals South Africa. “We have surplus capacity, across all areas of the facilities, to support market growth and we continuously strive towards lead time reduction to market. The LEAN manufacturing tools we use empower the facilities to reduce waste, improve on-time delivery (OTD) and shorten the lead times to market.”
The Alrode site, he continues, also houses our regional warehouse and distribution centre and the Linatex rubber facility, which manufactures rubber linings and mouldings for pumps, mills and made-to-order hose sections and bends. “We have just installed an amazing large screen test bay at this facility so we can test our locally manufactured large vibrating screens. While we have always manufactured a smaller range of vibrating screens, this testing facility caters for the larger double deck screens – our latest screen’s weight exceeds 50 tonnes – we have started to supply globally, mostly to Europe but also in Africa including Nigeria,” Govender says.
Towards sustainable energy use
To further the global Weir Minerals’ sustainability ambitions, the Isando facility has recently invested in a grid-tied solar power plant, which is now installed on the facility’s reinforced roof. “We have been systematically reducing our carbon footprint and are on track to reducing 50% of our total carbon emissions in the region. We have some amazing products that are designed to benefit customers in terms of energy and water efficiency, across our entire range of pumps and other products, such as our HPGRs. But we also believe we should be influencing the green and clean manufacturing agenda,” he explains.
“So, every part of our roof is now covered with solar panels, 2 181 of them, each capable of producing 540 kWp of power from the sun. This significantly reduces our dependence on municipal electricity but, more importantly, it reduces our carbon footprint for manufacturing. Since December, the new system has been supplementing the electricity needed for our machine shop, the rubber plant and the foundry areas,” Govender tells MechChem Africa, adding that the system is estimated to be saving more than 1 600 tons of carbon dioxide per year.
“While our location near the airport – a national keypoint – means we are less impacted by load shedding, the system gives us a sense of security from a business continuity perspective. We will now always have power to keep the facility up and running, excluding the furnaces, of course,” he says, adding that even on the furnaces, some grid-draw reductions also accrue due to savings on startup.
“The idea is to install systems at all three of our South African plants, and we are already looking to prepare the roof at Alrode in preparation for an installation there,” says Govender. “We hope to be able to run the whole Alrode plant off the solar system, because furnaces or other energy intensive processes don’t run there,” he adds.
Replicast moulding and Industry 4.0 Machining
Further supporting its sustainability goals, Weir Minerals Africa has also installed a Replicast plant for manufacturing casting moulds at its Isando facility. Replacing conventional wooden patterns and split sand moulds, this technology uses dimensionally precise ceramic cavity moulds made from expanded polystyrene replicas, Govender informs MechChem Africa.
A polystyrene replica of a casting is made first. This is then dipped several times into a ceramic-forming slurry to coat the surface. The coated polystyrene replica is then fired, which hardens the ceramic while completely removing the polystyrene, creating a very accurate ceramic shell that, when supported by sand, is used as the mould for casting. Because it is inert, the ceramic shell reduces the possibility of hydrogen defects, while also significantly improving the as-cast accuracy and surface finish of the product.
The Replicast process eliminates parting lines, cores, and draft angles from the completed casting, which reduces casting weight and fettling requirements. It also reduces machining requirements on a finished casting. Furthermore, the risk of gas, sand inclusions and hot-tear defects are significantly reduced. Combined with the improved moulding process, new Integrex Industry 4.0 machines have further improved machining efficiencies.
“Our Replicast plant has reduced the component turnaround, improved casting quality and reduced waste. Also, though, it further reduces the energy requirements and our carbon footprint,” he adds.
Because molten metal is no longer in direct contact with the casting sand, the Replicast system does not require the use of resin and catalyst for binding the supporting sand. Instead, Grade 30-35 AFS silica sand can be used which, prior to being compressed, is first passed through a vacuum bin to remove any air. And because the sand contains no acids or resins, it can be reused many times, which results in further environmental and sustainability advantages.
“In addition, the new system releases fewer harmful gases into the atmosphere during the casting process, further helping us to meet our corporate sustainability goals and to reduce environmental impacts,” says Govender.
Two new testing laboratories
To raise the bar with respect to safety, quality and customer satisfaction levels, Weir Minerals has established two new laboratories to further its world-class manufacturing capability. “We have equipped these labs with the latest technologies to align our manufacturing operations with global best-practice standards. A focus on quality assurance through the manufacturing process ensures good quality products and investing in upstream quality assurance has been part of the reliable supply success. Quick results mean the operation team can fine-tune the manufacturing processes, catch any discrepancies and implement changes very quickly. This helps us to optimise product availability and on time delivery,” he says, adding: “it gives customers a great deal of confidence in terms of product quality, lead times and supply certainty, while also reducing waste, rework and time lost repairing manufacturing defects.”
From a competitive point of view, the laboratory facilities also support research and development in improved equipment and materials, which further benefits customer operations. “By keeping our testing in-house, we are better able to protect our intellectual property. I think the other spinoff from this is that it contributes to skills development, encouraging staff to improve production processes and quality standards. It helps us to build-in a continuous improvement culture,” he adds.
Water harvesting
A further aspect of Weir Minerals’ drive to implement its global sustainability goals is that water harvesting has been implemented in all its South African manufacturing facilities. “Water used in our facilities is now being collected and reused in various other areas of the plants. At Isando, for example, where we need a lot of cooling water in the rubber shop, instead of having to draw on municipal water for this purpose, we can use collected and recycled water from the plant. And in the HBF plant in Port Elizabeth, which is a water scarce region, we have installed larger collection tanks to store more rain and recycled water, all of which is fully utilised in the facility,” says Rajen Govender.
“Our three local manufacturing sites enable us to deliver locally manufactured pumps and, depending on the application, product mix and customer’s installed base, we can typically claim between 60 to 80% local content for South African mines.
“We have very deliberately expanded our integrated solutions approach so we can offer solutions for everything from after blasting to tailings, including highly efficient processing solutions, such as our Cavex® hydrocyclones, Trio® crushers and Enduron® HPGRs.
“We are committed to the sustainable and efficient delivery of the World’s need for natural resources from African mines, and to a better and greener future for our planet,” Govender concludes.